Galaxy - replacing drivetrain, suggestions please?

[beanzontoast]

Beanz, you're doing what I've had to do with my 1988 Galaxy. I've put on a Stronglight Impact triple (28, 28, 48, I think), and gone for 700c cassette freehub wheels - although mine will take an 8-speed cassette. (In fact, the only original parts on it now are the brake cantilevers and the frame). I started out with a Shimano megarange cassette, but found that the jump from bottom-but-one gear(26 teeth I think) to bottom (34 teeth)was really too big. So I split the cassette up and put in a 30 toother from another cassette and left out one of the smaller sprockets which I rarely used,

I like the way that SRAM chains come with an easy to use joining link. An 8-speed chain will work on your cassette fine, and you can also get spare SRAM joining links with which to repair the chain.

What did you do about the gears, Phil? I'm assuming they were downtube shifters?

 

[Amanda P]

The bike originally had downtube friction shifters, of course.

Initially, I upgraded these to indexed shifters (once I had an indexable cassette rather than the original non-indexable freewheel).

More recently, I've upgraded to Campagnolo ten-speed ergopower brake levers/shifters. These work perfectly with Shimano 8-speed cassette spacing. (Don't know if the same is true of 7-speed. I think the spacing is the same, but the cassette's narrower... The Doc will advise on this, I'm sure, if necessary).

I was happy with my downtube shifters, but now I've experienced the luxury of being able to change gear without taking my hands off the bars, I'd find it hard to go back.

 

[Amanda P]

Incidentally, when I replaced the original Stronglight double chainset with a Stronglight Impact triple, I thought I might have to replace the bottom bracket. I didn't; the triple works fine on the same bottom bracket - but the chainline'd be better with a shorter axle.

I can't, however, remember whether the (cartridge) bb was the one that originally came with the bike. I doubt it - I think cartridge BBs were rare and exotic in 1988.

 

[Amanda P]

Oh, and I think the derailleurs themselves have been changed. When new it had Hurets, both of which broke in short order - they were crap. Even though the rear was the Duopar, which in the 80s bike magazines raved about.

The rear had a Shimano VX replacement, which worked fine on a 6-speed freewheel, but couldn't quite shift to the outer sprocket on an 8-speed cassette. There's now a long-cage XT which does a better job.

The front is still a sort of NHS-standard Shimano job, but it stuggles to shift to the outer chainring. Either I need to get a front derailleur better suited to the long throw needed for a triple, or the existing one will soldier on but with a shorter bottom bracket axle. Given the chainline problem which I've now acknowledged, changing the BB is probably the way to go...

 

[Landslide]

I'd like a chain that is durable but easy to repair in the field. Any suggestions what I should go for, bearing in mind the 7-speed cassette?

Another vote here for SRAM 7/8spd.
The PC-30 is cheap and cheerful (under £10) and will do the job just fine. As you spend more, they get shinier.

 

[TheDoctor]

More recently, I've upgraded to Campagnolo ten-speed ergopower brake levers/shifters. These work perfectly with Shimano 8-speed cassette spacing. (Don't know if the same is true of 7-speed. I think the spacing is the same, but the cassette's narrower... The Doc will advise on this, I'm sure, if necessary).

According to Chris Juden's Ultimate Guide to Gear Bodgery 8 speed sprockets are 4.8 mm apart, whereas 7 speed are 5 mm. It's close enough that 8-speed shifters will index 7 speed, but it's a bit marginal...

 

[PpPete]

Oh, and I think the derailleurs themselves have been changed. When new it had Hurets, both of which broke in short order - they were crap. Even though the rear was the Duopar, which in the 80s bike magazines raved about.

The rear had a Shimano VX replacement, which worked fine on a 6-speed freewheel, but couldn't quite shift to the outer sprocket on an 8-speed cassette. There's now a long-cage XT which does a better job.

The front is still a sort of NHS-standard Shimano job, but it stuggles to shift to the outer chainring. Either I need to get a front derailleur better suited to the long throw needed for a triple, or the existing one will soldier on but with a shorter bottom bracket axle. Given the chainline problem which I've now acknowledged, changing the BB is probably the way to go...

This bargain basement front mech works just fine on my triple (with a friction shifter on downtube) SJS seem to have loads they are auctioning off a few at a time.

 

[beanzontoast]

This bargain basement front mech works just fine on my triple (with a friction shifter on downtube) SJS seem to have loads they are auctioning off a few at a time.

Thanks for that link, mate.